1. Field of the Invention
The present invention relates to an illuminant, and, an electron beam detector, a scanning electron microscope and a mass spectroscope each including the same.
2. Related Background Art
Conventional electron beam detectors, at the time of measuring a high intensity electron beam, measure a current value caused by the electron beam to detect the electron beam. On the other hand, at the time of measuring an electron beam with a comparatively low intensity, the conventional electron beam detectors cannot successfully detect the electron beam because the electric charges caused by the electron beam is small. Thus, for example, an electron beam detector used for a scanning electron microscope (SEM) collects secondary electrons generated on a sample surface due to electron beam irradiation onto the sample surface, irradiates the collected secondary electrons onto a fluorescent substance, and measures fluorescence generated on the fluorescent substance by a photomultiplier (photodetector). As such a fluorescent substance, various fluorescent substances shown in FIG. 1 are known. Among these fluorescent substances, as one example, a luminous intensity (CL-intensity) due to electron beam irradiation of P47 is shown in FIG. 2. In the FIG. 2, the horizontal axis shows the wavelength (nm), the vertical axis shows the CL-intensity (in arbitrary units), and the peak wavelength of the CL-intensity of the P47 fluorescent substance is approximately 430 nm.
Recently, in the field of scanning electron microscopes and mass spectroscopes, a fluorescent substance having a high luminous intensity and a high response speed has been demanded. Because, for example, in scanning electron microscopes, a higher response speed of the fluorescent substance makes it possible to increase the scanning speed and improves performance of the device.